File revert-glib-bump-to-2.56.patch of Package qemu
From efea0974e013117b1c717f5b4ea299aab5520000 Mon Sep 17 00:00:00 2001
From: Jakub Jirutka <jakub@jirutka.cz>
Date: Wed, 10 Aug 2022 02:56:06 +0200
Subject: [PATCH] Revert "configure: bump min required glib version to 2.56"
This reverts commit b4c6036faa995a0ec00d45901aa722ab2dd14341.
---
configure | 2 +-
include/glib-compat.h | 13 ++-
util/oslib-win32.c | 204 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 216 insertions(+), 3 deletions(-)
diff --git a/configure b/configure
index 7c08c18358..1518c9aedc 100755
--- a/configure
+++ b/configure
@@ -2146,7 +2146,7 @@ fi
##########################################
# glib support probe
-glib_req_ver=2.56
+glib_req_ver=2.48
glib_modules=gthread-2.0
if test "$modules" = yes; then
glib_modules="$glib_modules gmodule-export-2.0"
diff --git a/include/glib-compat.h b/include/glib-compat.h
index 3113a7d2af..6b38847320 100644
--- a/include/glib-compat.h
+++ b/include/glib-compat.h
@@ -19,12 +19,12 @@
/* Ask for warnings for anything that was marked deprecated in
* the defined version, or before. It is a candidate for rewrite.
*/
-#define GLIB_VERSION_MIN_REQUIRED GLIB_VERSION_2_56
+#define GLIB_VERSION_MIN_REQUIRED GLIB_VERSION_2_48
/* Ask for warnings if code tries to use function that did not
* exist in the defined version. These risk breaking builds
*/
-#define GLIB_VERSION_MAX_ALLOWED GLIB_VERSION_2_56
+#define GLIB_VERSION_MAX_ALLOWED GLIB_VERSION_2_48
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
@@ -105,6 +105,15 @@ static inline gpointer g_memdup2_qemu(gconstpointer mem, gsize byte_size)
}
#define g_memdup2(m, s) g_memdup2_qemu(m, s)
+#if defined(_WIN32) && !GLIB_CHECK_VERSION(2, 50, 0)
+/*
+ * g_poll has a problem on Windows when using
+ * timeouts < 10ms, so use wrapper.
+ */
+#define g_poll(fds, nfds, timeout) g_poll_fixed(fds, nfds, timeout)
+gint g_poll_fixed(GPollFD *fds, guint nfds, gint timeout);
+#endif
+
#if defined(G_OS_UNIX)
/*
* Note: The fallback implementation is not MT-safe, and it returns a copy of
diff --git a/util/oslib-win32.c b/util/oslib-win32.c
index 4b1ce0be4b..54e4549558 100644
--- a/util/oslib-win32.c
+++ b/util/oslib-win32.c
@@ -327,6 +327,210 @@ const char *qemu_get_exec_dir(void)
return exec_dir;
}
+#if !GLIB_CHECK_VERSION(2, 50, 0)
+/*
+ * The original implementation of g_poll from glib has a problem on Windows
+ * when using timeouts < 10 ms.
+ *
+ * Whenever g_poll is called with timeout < 10 ms, it does a quick poll instead
+ * of wait. This causes significant performance degradation of QEMU.
+ *
+ * The following code is a copy of the original code from glib/gpoll.c
+ * (glib commit 20f4d1820b8d4d0fc4447188e33efffd6d4a88d8 from 2014-02-19).
+ * Some debug code was removed and the code was reformatted.
+ * All other code modifications are marked with 'QEMU'.
+ */
+
+/*
+ * gpoll.c: poll(2) abstraction
+ * Copyright 1998 Owen Taylor
+ * Copyright 2008 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+static int poll_rest(gboolean poll_msgs, HANDLE *handles, gint nhandles,
+ GPollFD *fds, guint nfds, gint timeout)
+{
+ DWORD ready;
+ GPollFD *f;
+ int recursed_result;
+
+ if (poll_msgs) {
+ /* Wait for either messages or handles
+ * -> Use MsgWaitForMultipleObjectsEx
+ */
+ ready = MsgWaitForMultipleObjectsEx(nhandles, handles, timeout,
+ QS_ALLINPUT, MWMO_ALERTABLE);
+
+ if (ready == WAIT_FAILED) {
+ gchar *emsg = g_win32_error_message(GetLastError());
+ g_warning("MsgWaitForMultipleObjectsEx failed: %s", emsg);
+ g_free(emsg);
+ }
+ } else if (nhandles == 0) {
+ /* No handles to wait for, just the timeout */
+ if (timeout == INFINITE) {
+ ready = WAIT_FAILED;
+ } else {
+ SleepEx(timeout, TRUE);
+ ready = WAIT_TIMEOUT;
+ }
+ } else {
+ /* Wait for just handles
+ * -> Use WaitForMultipleObjectsEx
+ */
+ ready =
+ WaitForMultipleObjectsEx(nhandles, handles, FALSE, timeout, TRUE);
+ if (ready == WAIT_FAILED) {
+ gchar *emsg = g_win32_error_message(GetLastError());
+ g_warning("WaitForMultipleObjectsEx failed: %s", emsg);
+ g_free(emsg);
+ }
+ }
+
+ if (ready == WAIT_FAILED) {
+ return -1;
+ } else if (ready == WAIT_TIMEOUT || ready == WAIT_IO_COMPLETION) {
+ return 0;
+ } else if (poll_msgs && ready == WAIT_OBJECT_0 + nhandles) {
+ for (f = fds; f < &fds[nfds]; ++f) {
+ if (f->fd == G_WIN32_MSG_HANDLE && f->events & G_IO_IN) {
+ f->revents |= G_IO_IN;
+ }
+ }
+
+ /* If we have a timeout, or no handles to poll, be satisfied
+ * with just noticing we have messages waiting.
+ */
+ if (timeout != 0 || nhandles == 0) {
+ return 1;
+ }
+
+ /* If no timeout and handles to poll, recurse to poll them,
+ * too.
+ */
+ recursed_result = poll_rest(FALSE, handles, nhandles, fds, nfds, 0);
+ return (recursed_result == -1) ? -1 : 1 + recursed_result;
+ } else if (/* QEMU: removed the following unneeded statement which causes
+ * a compiler warning: ready >= WAIT_OBJECT_0 && */
+ ready < WAIT_OBJECT_0 + nhandles) {
+ for (f = fds; f < &fds[nfds]; ++f) {
+ if ((HANDLE) f->fd == handles[ready - WAIT_OBJECT_0]) {
+ f->revents = f->events;
+ }
+ }
+
+ /* If no timeout and polling several handles, recurse to poll
+ * the rest of them.
+ */
+ if (timeout == 0 && nhandles > 1) {
+ /* Remove the handle that fired */
+ int i;
+ for (i = ready - WAIT_OBJECT_0 + 1; i < nhandles; i++) {
+ handles[i-1] = handles[i];
+ }
+ nhandles--;
+ recursed_result = poll_rest(FALSE, handles, nhandles, fds, nfds, 0);
+ return (recursed_result == -1) ? -1 : 1 + recursed_result;
+ }
+ return 1;
+ }
+
+ return 0;
+}
+
+gint g_poll_fixed(GPollFD *fds, guint nfds, gint timeout)
+{
+ HANDLE handles[MAXIMUM_WAIT_OBJECTS];
+ gboolean poll_msgs = FALSE;
+ GPollFD *f;
+ gint nhandles = 0;
+ int retval;
+
+ for (f = fds; f < &fds[nfds]; ++f) {
+ if (f->fd == G_WIN32_MSG_HANDLE && (f->events & G_IO_IN)) {
+ poll_msgs = TRUE;
+ } else if (f->fd > 0) {
+ /* Don't add the same handle several times into the array, as
+ * docs say that is not allowed, even if it actually does seem
+ * to work.
+ */
+ gint i;
+
+ for (i = 0; i < nhandles; i++) {
+ if (handles[i] == (HANDLE) f->fd) {
+ break;
+ }
+ }
+
+ if (i == nhandles) {
+ if (nhandles == MAXIMUM_WAIT_OBJECTS) {
+ g_warning("Too many handles to wait for!\n");
+ break;
+ } else {
+ handles[nhandles++] = (HANDLE) f->fd;
+ }
+ }
+ }
+ }
+
+ for (f = fds; f < &fds[nfds]; ++f) {
+ f->revents = 0;
+ }
+
+ if (timeout == -1) {
+ timeout = INFINITE;
+ }
+
+ /* Polling for several things? */
+ if (nhandles > 1 || (nhandles > 0 && poll_msgs)) {
+ /* First check if one or several of them are immediately
+ * available
+ */
+ retval = poll_rest(poll_msgs, handles, nhandles, fds, nfds, 0);
+
+ /* If not, and we have a significant timeout, poll again with
+ * timeout then. Note that this will return indication for only
+ * one event, or only for messages. We ignore timeouts less than
+ * ten milliseconds as they are mostly pointless on Windows, the
+ * MsgWaitForMultipleObjectsEx() call will timeout right away
+ * anyway.
+ *
+ * Modification for QEMU: replaced timeout >= 10 by timeout > 0.
+ */
+ if (retval == 0 && (timeout == INFINITE || timeout > 0)) {
+ retval = poll_rest(poll_msgs, handles, nhandles,
+ fds, nfds, timeout);
+ }
+ } else {
+ /* Just polling for one thing, so no need to check first if
+ * available immediately
+ */
+ retval = poll_rest(poll_msgs, handles, nhandles, fds, nfds, timeout);
+ }
+
+ if (retval == -1) {
+ for (f = fds; f < &fds[nfds]; ++f) {
+ f->revents = 0;
+ }
+ }
+
+ return retval;
+}
+#endif
+
int getpagesize(void)
{
SYSTEM_INFO system_info;
--
2.37.1
